This study examines how and why student teachers integrated technology to enhance instruction in elementary classrooms. The participants were 31 student teachers who completed an assignment of eight weeks. Multiple data sets including observation notes of 347 lessons were obtained from three key groups for data triangulation. Results reveal that the primary technological means used to enhance teaching was to provide visuals for attention, engagement and interaction. All participants chose to integrate technology but varied substantially in their teaching practices. They applied technology for a number of reasons: student engagement, time management, motivation and meeting individual students' needs. Variables such as influence of mentor teachers, technology access, skills, pedagogical competence and personal attitudes had an impact on their application. While most of them followed their mentor's practices, some student teachers took initiative and made contributions to their mentors' professional development in technology integration. Implications on teacher preparation programs are discussed.